Load bearing panel member

ABSTRACT

A load bearing panel member having a first portion, a second portion, and an appearance surface portion is formed by injection molding such that the first portion includes a plurality of ribs forming a grid pattern on the first portion and another plurality of ribs extending toward the periphery of the first portion which may be non-orthogonal to each other and to the ribs forming the grid pattern. An internal channel may be formed within each of the non-orthogonal ribs by injecting a gas into the rib during the molding process forming the panel. An appearance surface portion attached to the first portion and second portion of the panel member forms an integral hinge between the first and second portions of the panel member. The panel member may be configured as a floor panel of a vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Non-Provisional applicationSer. No. 14/837,322 filed Aug. 27, 2015, which is a continuation of U.S.Pat. No. 9,138,922 issued Sep. 22, 2015, which is a continuation of U.S.Pat. No. 8,764,101 issued Jul. 1, 2014, which is a divisionalapplication of U.S. Pat. No. 8,221,673 issued Jul. 17, 2012, whichclaims priority to U.S. Provisional Application No. 60/691,790 filedJun. 17, 2005, each hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention is drawn to a load bearing panel member formed bya method of injection molding.

BACKGROUND

There are numerous known systems for plastic injection molding. Inconventional plastic injection molding systems, plastic pellets aremelted in an injection molding machine and advanced by a screw ramthrough an injection nozzle and into a mold cavity. The mold cavity ispreferably formed between two mold halves. The molten plastic materialin the cavity is allowed to cool and harden in the cavity. When theplastic material has cooled and sufficiently hardened, the two halves ofthe mold are separated or opened and the part is removed, typically byone or more ejector pins.

Some injection molding systems utilize a gas in the injection moldingprocess and are commonly known as “gas-assisted injection molding”systems. In these systems, the gas is injected into the molten plasticmaterial through the plastic injection nozzle itself, or through one ormore pin mechanisms strategically positioned in the mold. It is alsopossible to inject the gas directly into the molten plastic in thebarrel of the injection molding machine. The gas, which typically is aninert gas such as nitrogen, is injected under pressure and forms one ormore hollow cavities or channels in the molded part.

Gas-assisted injected molding produces a structure having a hollowinterior portion which results in saving weight and material, therebyreducing costs. The pressurized gas applies an outward pressure to forcethe plastic against the mold surfaces while the article solidifies. Thishelps provide a better surface on the molded article and reduces oreliminates sink marks and other surface defects. The use of pressurizedgas also reduces the cycle time as the gas is introduced and/or migratesto the most fluent inner volume of the plastic and replaces the plasticin those areas which would otherwise require an extended cooling cycle.The pressure of the gas pushing the plastic against the mold surfacesfurther increases the cooling effect of the mold on the part, thussolidifying the part in a faster manner and reducing the overall cycletime.

SUMMARY

The present invention provides a method for producing a structural orload bearing injection molded panel member. According to one embodiment,the panel member is a floor panel for a van having retractable rearseats wherein the panel member is adapted to cover the rear seats whenfully retracted and act as a load floor. The panel member preferablyincludes a first portion, a second portion and an interior surfaceportion. The present invention will hereinafter be described accordingto an embodiment wherein the interior surface portion is a carpetmaterial; however, it should be appreciated that according to alternateembodiments the interior surface portion could also include, forexample, a vinyl material or a textile material.

An example method of the present invention includes placing the carpetmaterial into a mold cavity configured to produce the panel member. Themold cavity preferably includes a first chamber adapted to form thefirst portion of the panel member, and a second chamber adapted to formthe second portion of the panel member. After the carpet material isinserted into the mold, molten plastic material and pressurized gas areinjected into the first chamber of the mold cavity. After the moltenplastic material is injected into the first chamber of the mold, moltenplastic material is injected into the second chamber of the mold cavity.A sequential gating process is used to achieve this sequence ofoperations. The molten plastic is then cooled until it solidifies. Afterthe molten plastic is sufficiently cooled, the pressurized gas is ventedand the panel member is removed from the mold.

It should be appreciated that the order in which the steps of theexample embodiment are performed may be varied according to alternateembodiments. For example, according to one alternate embodiment of thepresent invention, the molten plastic material may be injected into thesecond chamber of the mold cavity before molten plastic material isinjected into the first chamber of the mold cavity. According to yetanother alternate embodiment, molten plastic may be injected into thefirst and second chambers of the mold cavity simultaneously.

The present invention also provides a structural or load bearing panelmember and a product by process. The load bearing panel memberpreferably includes a generally rectangular first portion, a generallyrectangular second portion, and a carpet material. The carpet materialis attached to the first portion and the second portion such that thecarpet material forms an integral or living hinge at a gap therebetween.The first portion of the panel member defines a plurality of solidhorizontally disposed ribs and a plurality of solid vertically disposedribs. The first portion of the load bearing panel member also includes aplurality of hollow ribs formed by the gas assisted injection moldingprocess. The hollow ribs are generally located around the periphery ofthe first portion of the load bearing panel member as well as in anX-shape originating at the center of the first portion and extendingtoward the corners thereof. The solid ribs and hollow ribs are adaptedto increase strength and rigidity and provide substantial structural orload-bearing capability

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom view of a load bearing panel member in accordancewith the present invention;

FIG. 2 is a block diagram illustrating a method of the presentinvention;

FIG. 3 is a sectional view of the panel member taken along line A-A ofFIG. 1;

FIG. 4a is a schematic sectional view of an injection molding nozzle anda plurality of valves; and

FIG. 4b is a schematic plan view of a mold cavity.

DESCRIPTION

Referring to the drawings, wherein like reference numbers refer to likecomponents, FIG. 1 shows a panel member 10 produced according to amethod of the present invention. The panel member 10 will hereinafter bedescribed as a floor panel for a van having retractable rear seats (notshown), wherein the panel member 10 is adapted to cover the rear seatswhen the seats are fully retracted and also to act as a load floor. Itshould be appreciated, however, that the method of the present inventionmay be implemented to produce other conventional panel members as well.

The panel member 10 includes a generally rectangular first portion 12, agenerally rectangular second portion 14, and an interior or appearancesurface portion 16 (shown in FIG. 3). The present invention willhereinafter be described according to the example embodiment wherein theinterior surface portion 16 is carpet material; however, it should beappreciated that according to alternate embodiments the interior surfaceportion 16 could also include, for example, a vinyl material or atextile material. According to one example embodiment, the carpetmaterial 16 is a polypropylene material with a polyester backing. Thecarpet material 16 is attached to the first portion 12 and the secondportion 14 such that the carpet material 16 forms an integral or livinghinge 18 at a gap 19 between the first portion 12 and the second portion14. The first portion 12 of the panel member 10 defines a plurality ofsolid horizontally disposed ribs 20 and solid vertically disposed ribs21. The solid ribs 20 and 21 are normal to each other so as to increasestrength and rigidity and provide substantial load-bearing capability.According to an example embodiment of the present invention, the secondportion 14 of the panel member 10 includes a plurality of up-standingclip attach members 22.

The clip attach members 22 preferably each retain a metallic attachmentclip (not shown) configured to mount the second portion 14 of the panelmember 10 to a seat assembly (not shown). When the seat assembly is inan upright position, the hinge 18 allows the second portion 14 of thepanel member 10 to fold underneath the first portion 12 and below theseat.

When the seat assembly (not shown) is fully retracted, the first portion12 of panel member 10 is rotatable about the integral hinge 18 from anopen position exposing the seat assembly to a closed position at whichthe seat assembly is covered. When the seat assembly is fully retractedand the first portion 12 of panel member 10 is in the closed position,the carpet material 16 (shown in FIG. 3) is exposed and the seatassembly is completely hidden. In this manner, the panel member 10 isadapted to provide an aesthetically pleasing carpeted interior when theseat assembly is retracted, and also provide substantial floor-strength.

Referring to FIG. 2, a method for manufacturing the panel member 10according to the present invention is shown. At step 50, the carpetmaterial 16 is placed into a mold cavity 70 (shown in FIG. 4b )configured to produce the panel member 10. Optionally, at step 50, metalinserts such as bars and/or tubes (not shown) can also be placed intothe mold cavity 70 with the carpet material 16 to produce a panel member10 with increased strength and rigidity. The mold cavity 70 of thepresent invention preferably includes a first chamber 72 (shown in FIG.4b ) adapted to form the first portion 12 of the panel member 10, and asecond chamber 74 (shown in FIG. 4b ) adapted to form the second portion14 of the panel member 10. The first and second chambers 72, 74 arepreferably separated by an insert or feature 75 (shown in FIG. 4b )configured to produce the integral hinge 18 (shown in FIG. 3). At step52, molten plastic material 76 (shown in FIG. 4a ) is injected into thefirst chamber 72 of the mold cavity 70. The molten plastic material 76is preferably injected in a conventional manner, such as, for example,by a reciprocating screw type injection device (not shown), through aninjector nozzle 40 (shown in FIG. 4a ), through a valve gate 42 a (shownin FIG. 4a ), and into the first chamber 72 of the mold cavity 70.

At step 54, an inert gas 80 (shown in FIG. 4b ) such as nitrogen isinjected into the first chamber 72 of the mold cavity 70 (shown in FIG.4b ) through a plurality of gas pins 82 (shown in FIG. 4b ) positionedat locations predefined by the desired locations of the hollow ribs 30.The gas 80 preferably does not mix with the molten plastic material 76,but takes the path of least resistance through the less viscous portionsof the plastic melt. The molten plastic 76 is therefore pushed againstthe wall portions of the mold cavity 70, which forms channels 31 andproduces the hollow ribs 30 (shown in FIGS. 1 and 3).

Referring to FIG. 3, a sectional view taken through section A-A of FIG.1 is shown. It can be seen in FIG. 3 that the hollow ribs 30 define aninternal channel 31 through which the gas is injected. Referring againto FIG. 1, the gas 80 (shown in FIG. 4b ) is preferably injected throughthe gas pins 82 (shown in FIG. 4b ) into the first portion 12 of thepanel member 10 at the gas injection locations 32. According to anexample embodiment, the hollow ribs 30 are generally located around theperiphery of the first portion 12 of the panel member 10 as well as inan X-shape originating at the center of the first portion 12 andextending toward the corners thereof. It has been observed that thehollow ribs 30 formed in the manner described increase the rigidity andstrength of the first portion 12 of the panel member 10. The increasedstrength and rigidity is particularly advantageous wherein the panelmember 10 is implemented as a load bearing floor panel.

Referring again to FIG. 2, at step 56 molten plastic material 76 (shownin FIG. 4a ) is injected into the second chamber 74 of the mold 70(shown in FIG. 4b ). The molten plastic material 76 is preferablyinjected through the injector nozzle 40 (shown in FIG. 4a ), through avalve gate 42 b (shown in FIG. 4a ), and into the second mold chamber74.

A sequential gating process is preferably implemented to performpreviously described steps 52 and 56. Referring to FIGS. 4a-4b , thevalve gates 42 a and 42 b, which are adapted to feed the first andsecond mold chambers 72, 74, respectively, are opened using thesequential gating process. In other words, the sequential gating processis implemented to control the timing of the gates 42 a, 42 b and tocoordinate the operation of valve gate 42 b with the operation of valvegate 42 a. According to an example embodiment, the valve gates 42 a and42 b are configured to open and close at a predetermined time. Thepredetermined time at which the valve gates 42 a and 42 b open and closeis generally based on the needs of the specific part to be molded andtype of material being used. Alternatively, the valve gates 42 a and 42b may be opened and closed based on the position of a screw typeinjection device (not shown).

Referring again to FIG. 2, at step 58 the molten plastic material 76(shown in FIG. 4a ) that was injected into the first and second chambers72, 74 of the mold cavity 70 (shown in FIG. 4b ) at steps 52 and 56 isallowed to cool and solidify. Thereafter, at step 60, the pressurizedgas 80 (shown in FIG. 4b ) that was injected in to the first chamber 72of the mold cavity 70 at step 54 is allowed to vent through the gas pins82 (shown in FIG. 4b ). At step 62, the finished panel member 10 isremoved from the mold cavity 70.

It should be appreciated that the order in which the steps 50-62 of theexample embodiment are performed may be varied according to alternateembodiments. For example, according to one alternate embodiment of thepresent invention, step 56 at which the molten plastic material 76(shown in FIG. 4a ) is be injected into the second chamber 74 (shown inFIG. 4b ) of the mold cavity 70 (shown in FIG. 4b ) may be performedbefore step 52 at which molten plastic material 76 is injected into thefirst chamber 72 (shown in FIG. 4b ) of the mold cavity 70. According toyet another alternate embodiment, steps 52 and 56 may be performedsimultaneously such that molten plastic 76 is injected into the firstand second chambers 72, 74 of the mold cavity 70 simultaneously.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

The invention claimed is:
 1. A load bearing panel member for a vehicle,comprising: a first portion including: a first plurality of rib membersformed on the first portion; wherein each rib member of the firstplurality of rib members is parallel to each other rib member of thefirst plurality of rib members; a second plurality of rib members formedon the first portion and extending toward a periphery of the firstportion, wherein each rib member of the second plurality of rib membersis non-orthogonal to another rib member of the second plurality of ribmembers and non-orthogonal to each rib member of the first plurality ofrib members; wherein a hollow cavity is defined within each of thesecond plurality of rib members; a second portion; and a living hingeintermediate the first and second portions; wherein the living hingecomprises an appearance surface material.
 2. The load bearing panelmember of claim 1, further comprising: a third plurality of ribs;wherein each rib of the third plurality of ribs is orthogonal to eachrib of the first plurality of ribs.
 3. A load bearing panel member for avehicle, comprising: a first portion including: a first plurality of ribmembers formed on the first portion; wherein each rib member of thefirst plurality of rib members is parallel to each other rib member ofthe first plurality of rib members; a second plurality of rib membersformed on the first portion and extending toward a periphery of thefirst portion, wherein each rib member of the second plurality of ribmembers is non-orthogonal to another rib member of the second pluralityof rib members and non-orthogonal to each rib member of the firstplurality of rib members; wherein a hollow cavity is defined within eachof the second plurality of rib members; a second portion; and a livinghinge intermediate the first and second portions; wherein: the firstportion is made of a first material; the living hinge is made of asecond material; and the first and second materials are differentmaterials.
 4. The load bearing panel member of claim 3, wherein theliving hinge comprises an appearance surface material.
 5. The loadbearing panel member of claim 1, wherein a span of the appearancesurface material separates the first portion and the second portion. 6.A load bearing panel member for a vehicle comprising: a first portionincluding: a first plurality of rib members positioned adjacent aperiphery of the first portion; a second plurality of rib members formedon the first portion and extending toward the periphery of the firstportion, wherein each rib member of the second plurality of rib membersis non-orthogonal to another rib member of the second plurality of ribmembers and non-orthogonal to each rib member of the first plurality ofrib members; wherein a hollow cavity is defined within each rib memberof the first plurality of rib members; wherein each rib member of thesecond plurality of rib members is a hollow rib member; a secondportion; and a living hinge spanning a gap between the first and secondportions.
 7. The load bearing panel member of claim 6, furthercomprising: a third portion attached to the first and second portions;wherein the third portion includes the living hinge.
 8. A load bearingpanel member for a vehicle comprising: a first portion including: afirst plurality of rib members positioned adjacent a periphery of thefirst portion; a second plurality of rib members formed on the firstportion and extending toward the periphery of the first portion, whereineach rib member of the second plurality of rib members is non-orthogonalto another rib member of the second plurality of rib members andnon-orthogonal to each rib member of the first plurality of rib members;wherein a hollow cavity is defined within each rib member of the firstplurality of rib members; a second portion; a living hinge spanning agap between the first and second portions; and a third portion attachedto the first and second portions; wherein the third portion includes theliving hinge; and wherein the third portion includes an appearancesurface material.
 9. The load bearing panel member of claim 6, wherein:the first portion includes a metal insert configured to increase therigidity of the first portion.
 10. The load bearing panel member ofclaim 8, wherein each rib member of the second plurality of rib membersis a hollow rib member.
 11. The load bearing panel member of claim 6,wherein second portion includes at least one clip configured to attachthe panel member to the vehicle.
 12. The load bearing panel member ofclaim 6, further comprising: a third plurality of rib members formed onthe first portion; wherein each rib member of the third plurality of ribmembers is parallel to each other rib member of the third plurality ofrib members; and wherein each rib member of the third plurality of ribmembers is parallel to each rib member of the first plurality of ribmembers.
 13. The load bearing panel member of claim 12, wherein each ribmember of the third plurality of rib members is non-orthogonal to eachrib member of the second plurality of rib members.